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Antigen presentation is a vital immune process that is essential for T cell immune response triggering. Because T cells recognize only fragmented antigens displayed on cell surfaces , antigen processing must occur before the antigen fragment can be recognized by a T-cell receptor .
Dedicated antigen-presenting cells, including macrophages, B cells and dendritic cells, present foreign antigens to helper T cells, while virus-infected cells (or cancer cells) can present antigens originating inside the cell to cytotoxic T cells. In addition to the MHC family of proteins, antigen presentation relies on other specialized ...
Macrophages supply both signals required for T helper cell activation: 1) Macrophages present antigen peptide-bound MHC class II molecule to be recognized by the corresponding T cell receptor (TCR), and 2) recognition of pathogens by PRRs induce macrophages to upregulate the co-stimulatory molecules CD80 and CD86 (also known as B7) that binds ...
MHC Class II molecules are a class of major histocompatibility complex (MHC) molecules normally found only on professional antigen-presenting cells such as dendritic cells, macrophages, some endothelial cells, thymic epithelial cells, and B cells. These cells are important in initiating immune responses.
Each antibody recognizes a specific antigen unique to its target. By binding their specific antigens, antibodies can cause agglutination and precipitation of antibody-antigen products, prime for phagocytosis by macrophages and other cells, block viral receptors, and stimulate other immune responses, such as the complement pathway.
After the processed antigen (peptide) is complexed to the MHC molecule, they both migrate together to the cell membrane, where they are exhibited (elaborated) as a complex that can be recognized by the CD 4+ (T helper cell) – a type of white blood cell. [note 7] [20] This is known as antigen presentation.
Antigen presentation stimulates naïve CD8+ and CD4+ T cells to become mature "cytotoxic" CD8+ cells and "helper" CD4+ cells respectively . During an immune response, professional antigen-presenting cells (APCs) endocytose antigens (typically bacteria or viruses), which undergo processing, then travel from the infection site to the lymph nodes ...
Antigen processing, or the cytosolic pathway, is an immunological process that prepares antigens for presentation to special cells of the immune system called T lymphocytes. It is considered to be a stage of antigen presentation pathways.